Telomeres

May 13, 2002

Telomeres, the repeated sequence found at the ends of chromosomes, shorten in many normal human cells with increased cell divisions. Statistically, older people have shorter telomeres in their skin and blood cells than do younger people.53,54 In the animal kingdom, though, long-lived species often have shorter telomeres than do short-lived species, indicating that telomere length probably does not determine life span.55,56,57 Solid scientific evidence has shown that telomere length plays a role in determining cellular life span in normal human fibroblasts and some other normal cell types.58 Increasing the number of times a cell can divide, however, may predispose cells to tumor formation.59,60 Thus, although telomere shortening may play a role in limiting cellular life span, there is no evidence that telomere shortening plays a role in the determination of human longevity.